Elisabeth C. Miller Library logo Miller Library Home UW Botanic Gardens Home UW Botanic Gardens Home book graphic

3501 NE 41st Street, Seattle, WA 98195 | (206) 543 0415 | Open: | Library Schedule

Gardening Answers Knowledgebase

Plant Answer Line Question

Keywords: Verticillium, Plant diseases--Diagnosis, Acer

I want to test the roots of our Japanese Maple for Verticillium wilt. Are there places which could test for that?


There is information about Verticillium wilt and how to manage it on the Washington State University Extension's HortSense website.

To have a sample from your Japanese maple diagnosed, you can take samples to a free Master Gardener Clinic, or you can send samples (for a fee) to WSU Puyallup Research and Extension Center:
go to "How to Submit a Sample," scroll down to "Plant Problem Diagnosis," then you can download a form by clicking on "Form C1006."

My personal experience with this disease is that the Japanese maple lived with it for quite a few years before totally succumbing, at which point we had it removed by an arborist.

Date 2017-06-09
Link to this record only (permalink)

Plant Answer Line Question

Keywords: Verticillium, Tomatoes--Diseases and pests

I was just outside checking on the slow ripening progress of my tomato plants and noticed something that has me concerned. There seems to be a fungus or mold at the very base of my "super fantastic" tomato plant. Other than this issue and the slow ripening the plant seems to be doing okay. I haven't noticed this fungus/mold before so I don't know if has just appeared and is spreading rapidly or if it has been there all along. Do you know what it is? Will it spread through the entire plant? Will it spread to the other tomato plants and veggies in this bed? Should I remove the entire plant?


This sounds a lot like Fusarium wilt, but it could also be Verticillium (another fungal problem) or even walnut toxicity (do you have any black walnut trees within 50 feet of your plants?). It might even be excessive watering which is causing the problem.

According to The Organic Gardener's Handbook of Natural Insect and Disease Control edited by Barbara Ellis (Rodale, 1996), you can cut open a stem near the soil line and look for internal discoloration. Verticillium affects the whole plant, while Fusarium will start by infecting individual shoots and then spread. Tomato Fusarium only affects tomatoes, while there are numerous plants which are susceptible to Verticillium. The best thing to do if your plant is suffering from these fungal diseases is to destroy them, so you may want to take a sample to a Master Gardener Clinic for diagnosis before you do anything drastic.

General resources on tomato problems:

Recognizing Tomato Problems from Colorado State University Extension.

Vegetable MD Online from Cornell University.

University of California, Davis Integrated Pest Management has excellent pictures of the insides of the stems, for comparison.

Date 2017-02-11
Link to this record only (permalink)

Garden Tip

Keywords: Biofumigation, Quercus alba, Malus sylvestris, Verticillium, Ginkgo biloba, Liquidambar, Katsura, Fraxinus, Pseudotsuga menziesii, Malus domestica

Don't despair if verticillium wilt lives in your garden's soil because there are many resistant plants. A few verticillium-resistant trees include Apple and Crabapple, Mountain Ash, Ginkgo, Sweet Gum, Katsura, Douglas Fir, Arborvitae and White Oak. A long list of susceptible and resistant trees, shrubs, perennials and vegetables.

There is some evidence that broccoli (chopped up new shoots worked into the soil) can act as a soil fumigant, if added to the soil before planting. Studies were done by Krishna Subbarao at University of California, Davis, and showed reduced incidence of wilt in cauliflower crops where broccoli had been planted and its residue added to the soil.

Date: 2007-05-23
Link to this record (permalink)

Garden Tip

Keywords: Soilborne plant diseases, Fungal diseases of plants, Verticillium, Maple

Verticillium wilt is making an appearance now as trees and shrubs begin to leaf out. Maple trees are especially susceptible. The sudden wilting and death of one or two branches in an otherwise healthy looking tree is the one obvious symptom. If this soil- borne disease attacked early in spring, tree branches may not have leafed out at all. Cutting into an affected branch typically reveals dark streaks. Control is difficult, but sometimes a tree can be preserved for a few years by cutting out the diseased wood and eliminating environmental stress such as drought. Make sure to disinfect pruning tools between cuts to avoid spreading the fungus. No fungicides for verticillium are registered for homeowners in Washington. For more information read Washington State University Cooperative Extension online article.

Date: 2007-05-23
Link to this record (permalink)

Didn't find an answer to your question? Ask us directly!

Browse keywords

Search Again:

August 01 2017 12:36:01